Cops Insane 'The Godfather' Watch

A WATCH YOU CAN'T REFUSE

Antonio Brown's decided to treat himself following the success of his new song and dance by copping an insane "The Godfather" watch ... that's filled with 666 diamonds!

TMZ Sports has learned the former NFL wideout hit up Jacob and Co. earlier this week to pick up the timepiece ... and the classic mob film-inspired watch came pretty epic.

We're told it features a miniature Vito Corleone (played by actor Marlon Brando) in the middle of it with his iconic black tux. It also has a hand-painted black piano ... and a Swiss music box that plays the first 120 notes of the movie's theme song!

And, get this ... the music box is played by two cylinders that are paved with 666…